Maes
I like big butts!
Posts: 8662
Registered: 07-06 |
printz said:
To get back on topic. Is Doom really that easy to port?
It is, if an ANSI C compiler that can handle it is available for the target platform. The game logic can remain intact and, if you are simply porting Linuxdoom 1.10, you don't need to understand how the renderer works or how a fixed_t is really a 16.16 fixed precision number or any of that stuff: you let the compiler handle these aspects.
What you MUST provide, however, are platform specific drivers that actually let you provide doom with event_t objects (user input), and in turn allow Doom's video buffers to be drawn on your platform's screen (in turn, this generates the requirement that you can use an 8-bit palette-based display directly, or else you have to provice an additional conversion step).
Optionally, you can also implement networking and sound interfaces/drivers. Probably you must also accomodate for file/resource management on your specific platform, if the standard C library functions wouldn't do the trick.
TL; DR: With a C compiler and software mode rendering, you can literally only write this part of the code and never take as much as a glimpse at the rest of the game logic.
If you are attempting something like Mocha Doom or an OpenGL port OTOH, you must literally lay eyes on every line of code and understand how everything is supposed to work together, and what actual structures it maps to.
printz said:
Also 700kB of program doesn't seem this easy to cram into an embedded software, but what do I know...
That particular calculator is easily one of the most powerful ever made. It's based on a 90 MHz ARM processor and it actually has 32 MB of work RAM to play with, so it actually smokes most DOS-era 486s and even some early Pentiums in everything but graphics. The next more powerful in its manufacturer's line is much, much lower on specs (68000 CPU and 512 KB of RAM), and on that it wouldn't be possible. Doom needs a 386-class CPU and 4 MB of RAM to be usable without cutting down resources (like console versions do).
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02-26-11 11:29 
